Electric fans and thermostats

[trestlehed]

Hi all,

Last year I had a mechanic buddy replace my fan clutch with dual 9 inch electric fans by Jeggs. At the time he replaced the hose of death and the coolant water outlet plate, then fully flushed the system. The relays he bought were set to turn the fans on when the engine temp reaches 185 degrees, and turn off at 170. The stock oem Toyota thermostat opens up at 180. So the initial problem was that the thermostat was not fully open by the time the fans kicked on. So he got an aftermarket thermostat rated for 170 - 175 F (can't remember which). Everything worked great up till about 7 months ago when my expansion tank started to overflow. My engine is not overheating as the temp gauge never gets to halfway before the fans kick on and cool things down. So right now I'm guessing that the aftermarket thermostat is not opening. Here's why: A couple days ago I tried to do the exhaust gas-in-coolant test with a kit I bought at Napa.
As the engine warmed-up I had to continually suck coolant out of the filler neck with a turkey baster. After close to 15 minutes the coolant kept coming out faster and faster until I couldn't keep up with it as well as it getting too hot to handle in the turkey baster. I shut off the engine for a couple minutes then tried to do the exhaust gas test, but once again the coolant started coming up again. My test was inconclusive.

So my plan now is to remove the current thermostat (test it to see if it stuck shut or not), then put in another aftermarket one rated at 170 F and drill a 3/16th hole in the top housing as a cheap insurance policy. In addition, my mechanic buddy is looking into changing the fans on/off temps with new relays.
I was thinking new fan temps should be: fans on at 185 F and fans off at 175 - 178 F.

Another thought is that one of the previous owners may have had the head gasket replaced with an aftermarket one and as a result, some of the water jackets are blocked... Don't want to go there quite yet.

Any ideas or thoughts on all this?

[timsrv]

Keep in mind that coolant expands as it's heated so it can be normal for it to come out of an open filler port while the engine is heating (that's what the overflow tank is for). Still, once heated the volume of coolant will remain constant...............so if it still keeps coming out that's an indication of something strange going on. Any time you are having a cooling issue it's probably a good idea to just replace the engine thermostat. I would however avoid aftermarket and use Toyota part# 90916-03046 that's set to 82c (180f). Don't forget to get a new rubber gasket (Toyota part#16325-63011).

I'm not sure what are you talking about when you say "drilling a 3/16" hole". The engineers at Toyota put a lot of thought into this so don't muck things up by drilling holes!!!

As for the electric fan t-stats, keep in mind that with the 180f t-stat normal temps at the head will be around 195f-205f. This means fans should be set to come on at around 200f-205f (head coolant temp). If you set it to shut off any lower then there's not much point in having a fan t-stat at all (fans will run all the time anyhow). I wouldn't mess around with installing a lower temp engine t-stat as these engines were designed to run with the 180f one here.

I don't know what type of fan t-stat you have, but I highly recommend one that has a sense probe immersed in coolant (the most accurate way to control fans). On my electric fan set-up I use an adjustable thermostat that has a range of around 150-230 deg f. I have it set to come on at around 205f and shut off at around 200f. It has a long capillary tube with a 1/4" probe on the end that I placed in an extra port in the cylinder head. Works great. Good luck with your problem, hopefully it's just a stuck engine t-stat. Tim

[trestlehed]

Tim,

My mechanic buddy Steve put the temp sensor in the extra port just like you described (see attached pic).
He also thinks I have a stuck (closed) thermostat based on my test the other day where the hot coolant would keep coming up out of the filler neck. He is checking with Jeggs, the electric fan maker, to see if we can get some new relays to change the fan on/off temps. If so, we'll go with the temps you suggested here.

Will let you know what I find and the proposed fix.

Thanks again for your help!

-Mark H.

[timsrv]

That's good it's immersed, but the only way to adjust that style is to change out the temp switch (that brass part installed in your head). That brass part is a non-adjustable temp controlled on/off switch (it's preset at the factory). Your mechanic is most likely using it to trigger relay(s), but the temp at which they activate is controlled entirely by that switch. A better way to go is an adjustable type t-stat......that way you can easily change the activation temp by simply turning a dial. Once you find the sweet spot just leave it alone and you're good. IMO, that spot is when the van can run without the fan on a cold day, but when you stop for a while (engine running but no air flow through the radiator) the fan will cycle on/off to maintain a constant engine temp. Based on my experience that spot is right around 200f-205f. Here's a picture of my fan t-stat set-up. I use this t-stat to power up a 30A Bosch style relay. The relay bridges power directly from my battery to the fans. For a while I was using an ignition switched circuit, but changed to a direct battery hook-up as to avoid the "hot soak" issue. Now fans switch on/off for a while after the van is shut-off insuring quick & easy restarts on hot days. Tim





Fan temp settings aside, it worries me a bit your coolant continues to be "pushed" out of the filler neck after warm-up. Usually when we see that it means combustion gasses are entering the cooling system (blown head gasket). Still, I wouldn't jump right to that conclusion without 1st investigating the condition of your engine t-stat. If you do end up doing a head-gasket you'll want to replace the engine t-stat anyhow, so it's just a good idea to try swapping that out 1st. Cross your fingers and give it another try. Good luck. Tim

[trestlehed]

Wow, I didn't know there was such a thermostat dial control. Cool!
looks like another gadget I must have!

I just found one here:

http://www.jegs.com/i/Flex-a-lite/40...oductId=751522

Thank you Tim!

[trestlehed]

Tim,

From my mechanic Steve:

Maybe the best thing is to work out with Tim whats best for your van and I'll install it.

Which brand of temp switch did you use and how can I find it? The one from Jegs has only two prongs on the box and yours has three.
So if the Jegs version doesn't work I'll need to look elsewhere.

Thanks,
-Mark

[timsrv]

Mine has the option of being normally open or normally closed (thus the 3 terminals), but for this application only the normally open terminals are needed............so I'm only using 2 of them (the ones for normally open). I'm sure the one you linked to is for normally open use only (which is what you want anyhow). In short, I think the one in your link is a good choice & a good price.

I didn't see the size of the probe listed, but it looks like 1/4". To make the transition from the 1/4" sensor to 16mm X 1.5 pitch threads (the size of the head port), I purchased a brass adaptor at the local hardware store. It originally was 3/8"mpt on one end and 1/4" compression on the other (these are readily available almost everywhere). I also purchased a 16mm X 1.5 die and simply chased the slightly larger 3/8" threads to convert to metric. The larger size 3/8 pipe thread was almost too big to chase without turning in a lathe, but with a little effort and patience this can be done by hand with only a vice and hand threading tools. After chasing, the new metric threads were perfect. Tim

[Dogfish]

I'm in the process of installing a thermostat on a van I recently bought. It had an electric fan (switched) already but I wanted to install a thermostat. I bought the 3/8ths fitting, cut metric threads and it installs fine. I also have the 1/4in compression fitting necessary to reduce it.

I noticed that I only have about 3 feet of (tube?) between the probe and the thermostat control. I was wondering where you decided to mount your control unit. I didn't see it in the pictures and you didn't talk about it.

Thanks
-Jim

[timsrv]

Here is where I mount them:


The one in the picture is a Flex-a-Lite control box, but this is a good location (it has this same t-stat inside). If you have kids with busy feet & fingers then I'd either find another spot or cover it with some sort of box. I'm thinking about trying one of the new Flex-a-Lite control boxes that use the electronic t-stat with variable speed. The old style capillary type t-stats seem to fail every couple years. When my 1st one failed I thought it was maybe a fluke, but the 2nd one (about 2 years old now) is starting to act weird too. Of course the electronic one may not be any better, but I like the idea of it because I can mount anywhere (sensor wire can be any length). Capillary tubes are fragile too, so be careful not to bend too sharp and protect it from chaffing. I would also recommend reducing the load on the t-stat by using a relay. Tim

[trestlehed]

Update: I haven't done anything since my last post here due to my mechanic having injured his shoulder at work followed by surgery. In addition he is having knee replacement surgery in Early April and thinks he can start working on my van in mid April.

My wish list is large: fix cooling system gremlins (new T-stat, new relays for electric fans with new temp settings) and new OEM head gasket, new water pump, tps, O2 sensor. Remove rear heater and associated hoses (especially the low hanging one running crosswise under the van). New fusible link (the one under and forward of the battery tray). Possibly some new VSV's and BVSV if needed.
Fix exhaust manifold leak, check fuel injectors and clean/replace if needed. My van passed smog 2 months ago, but the tech said some codes were showing and the van was running a little rich.

Basically I want most of the hard-to-do items tackled so I won't have to deal with them in the near future.

Tim, once the work begins I'll probably have Steve my mechanic log-on as a member so I won't have to relay info to you all the time (cutting out the middle-man), if that's ok with you?

-Mark

[timsrv]

Tim, once the work begins I'll probably have Steve my mechanic log-on as a member so I won't have to relay info to you all the time (cutting out the middle-man), if that's ok with you?

-Mark

No problem. I'd be happy to work with him. Tim

[timsrv]

Just to help everybody get a better mental picture here is some more information on the thermostat control box I showed in my picture above. This control box is Flex-a-Lite #30332. it's really nothing special as it simply incorporates the t-stat, a couple of diodes, and a relay. I say "nothing special" because the same thing can be easily accomplished with the individual components listed above. I just like it because it keeps things clean and provides a compact/handy package........This saves time with wiring, keeps things protected, and looks professional.

I happen to have an extra control box and t-stat laying around so I took some pics:






Here's the Flex-a-Lite control box with the cover off sitting next to a replacement thermostat.


Here's the guts. Just a thermostat, a relay, and a couple of diodes. The PC board is only an alternative for wires and it serves as a base for the spade connectors.




I'm also attaching a PDF of the installation instructions for anybody interested. Tim

[djshimon]

Thanks for all the good info Tim. That controller really is simple. Isn't that the capillary type probe that you said breaks every couple years? I noticed they sell a replacement board with relay for 29$-maybe that would be the fix? Anyway, I tried to find the electronic temp probe and couldn't, I'll keep looking. I'm hoping to finally get that pusher fan in this spring-gotta love long, cold winters to keep hot engines happy.

[timsrv]

Yeah, my 1st thermostat lasted about 2 years (and I had it protected with a relay). I replaced it with another (the same thing). That was about 2 years ago and although it's still working it acts weird (at times it clicks on and off a lot........like for a second or less). I think it's on it's way out. Regardless, I don't trust it anymore so I'm thinking about trying their new style. I just checked Amazon and see they list all of these. Here are links to them. Tim

http://www.amazon.com/Flexalite-3033...3043290&sr=8-6

http://www.amazon.com/Flex---lite-31...3043290&sr=8-2

http://www.amazon.com/Flex---lite-31...3043290&sr=8-1

Edit:......Lol, I just read the reviews. After reading these I'm definitely going to try the #31165 unit (last link).

[djshimon]

Awesome. Thanks again. The reviews do look good for the last one that you like. I didn't notice it saying electronic or capillary but the last reviewer said it can be converted from "probe style temp to NPT style ANYtime i want"-I'm guessing you couldn't do that with capillary type.
Any chance yours just broke due to a cheaply manufactured relay?

[timsrv]

T-stat failed. Not sure what is failing this time around......perhaps the relay. Regardless, I decided to go with the one in the last link. I just purchased from Amazon and will post pics and a product review when I get it and install it. Tim

[trestlehed]

T-stat failed. Not sure what is failing this time around......perhaps the relay. Regardless, I decided to go with the one in the last link. I just purchased from Amazon and will post pics and a product review when I get it and install it. Tim

Hi Tim,

Any update on the new relay unit? I'm getting ready to have this done soon.

[timsrv]

I got it and installed it shortly after that post. I used it for almost a whole day before a woman driving the wrong way without a driver's license or insurance totaled my van (while it was parked). Anyhow, I plan on fixing that van but it's still "out of service"............but hey, the fan still works . Tim

[trestlehed]

I got it and installed it shortly after that post. I used it for almost a whole day before a woman driving the wrong way without a driver's license or insurance totaled my van (while it was parked). Anyhow, I plan on fixing that van but it's still "out of service"............but hey, the fan still works . Tim

OMG that sucks! Glad you were not in it at the time. Reminds me of back in Dec. 2006 a guy driving home from his night shift fell asleep at the wheel of his giant Dodge utility work truck and plowed into my parked 1982 Celica (inherited from my dad/just had recent major work done to it $$). Knocked it up onto the sidewalk. Ins. Co. totaled it as it was a unibody frame and unfixable.

Good thing you have like 10 other vans to choose from!

[trestlehed]

Tim,

My mechanic Steve is about to do the manual temp relay installation.
Any news on the newer electronic ones.

I think the one I bought from Jeggs has the capillary tube sensor.

Thanks